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A unified stochastic damage model for concrete based on multi-scale energy dissipation analysis

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Science China(Technological Sciences) 2024年第3期67卷 863-877页

作者： GUO ChengGong LI jie College of Civil Engineering Tongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Shanghai 200092China

This work proposes a unified damage model for concrete within the framework of stochastic damage mechanics. Based on the micro-meso stochastic fracture model(MMSF), the nonlinear energy dissipation process of the microspring from nanoscale to microscale is investigated. In nanoscale, the rate process theory is adopted to describe the crack growth rate;therefore, the corresponding energy dissipation caused by a representative crack propagation can be obtained. The scale gap from nanoscale to microscale is bridged by a crack hierarchy model. Thus, the total energy dissipated by all cracks from the nanoscale to the microscale is gained. It is found that the fracture strain of the microspring can be derived from the above multi-scale energy dissipation analysis. When energy dissipation is regarded as some microdamage to the microspring, the constitutive law of the microspring is no longer linearly elastic, as previously assumed. By changing the expression of the damage evolution law from fracture strain to energy dissipation threshold, the new damage evolution model is derived. The proposed model can not only replicate the original static model but also extend to cases of rate dependence. By deriving the fracture strain under different strain rates, the rate sensitivity of concrete materials can be reflected. The model parameters can be conveniently obtained by identifying them with experimental data. Finally, several numerical examples are presented to verify the proposed model.

关键词： concrete damage model stochastic damage rate dependent energy dissipation

Dual-band terahertz antenna based on a novel photonic band gap structure

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Optoelectronics Letters 2023年第11期19卷 666-672页

作者： BAI Yukun LI jie Tianjin Key Laboratory of Film Electronic and Communication Devices Engineering Research Center of Optoelectronic Devices and Communication TechnologyMinistry of EducationSchool of Integrated Circuit Science and EngineeringTianjin University of TechnologyTianjin300384China

In this paper,a novel dual-band photonic band gap(PBG) structure was proposed and applied to a dual-band micro-strip antenna.The antenna resonates at 1.267 THz and 1.502 THz,exhibiting reflection coefficients of-58.177 dB and-49.462 dB,and gains of 3.173 dBi and 5.232 dBi,respectively.Compared with the microstrip antenna based on the homogeneous silicon substrate,the designed dual-band antenna based on the novel PBG structure shows improved impedance matching,radiation efficiency,and gain.The paper simulated and analyzed the impacts of different filling dielectric materials and the variations of dimensions,position,period,and corrugation depths of the dual-band PBG structure on the resonances of the antenna.It is expected that the proposed novel dual-band PBG structure has great application potentials,and such cancer diagnosis is done by utilizing the radiation characteristics of the antenna.

关键词： antenna structure band

Typhoon hazard assessment at the site-specific scale based on the probability density evolution method and its application on the southeast coast of China

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Science China(Technological Sciences) 2023年第1期66卷 86-100页

作者： HONG Xu LI jie Collegeof Civil Engineering Tongji UniversityShanghai 200092China

Herein, a typhoon hazard assessment method at the site-specific scale is proposed. This method integrates the nonlinear threedimensional wind field model and the probability density evolution method. At the site-specific scale, the track of a typhoon near the engineering site is approximated via a straight line. The wind field model is utilized to calculate the wind speed at the surface given the gradient wind field at the top of the boundary layer. A comparison between the simulated and observed wind histories for Typhoon Hagupit that made landfall in Guangdong Province demonstrates the fidelity of the wind field model. The probability density evolution method is utilized to calculate the propagation of the randomness from the basic random variables toward the extremities of the typhoon surface wind. To model the probability distribution of the basic random variables, several candidate distributions are considered to fit the observations. Akaike information criterion and Anderson-Darling distance are used for selecting the preferred probability distribution model. The adequacy of the probability density evolution method in assessing typhoon hazards is verified by comparing the results with those generated by Monte Carlo simulations. The typhoon wind hazards estimated by the present study are compared with those proposed by other studies and the design code, and the differences are analyzed and discussed. The results of the proposed method provide the reasonable probabilistic model for the assessment of the structural reliability and the improvement of community resilience in the typhoon-prone areas.

关键词： typhoon hazard Akaike information criterion Anderson-Darling distance boundary-layer wind field probability density evolution method

21世纪以来中国的分裂主义研究——李捷教授访谈

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国际政治研究 2022年第6期43卷 131-155页

作者：李捷靳晓哲兰州大学中亚研究所

分裂主义作为现代民族国家体系的伴生物,是一种相对普遍而又特殊的国际现象。伴随着世界三次民族主义浪潮,分裂主义在全球的肆虐未有穷期。特别是在后冷战时代,国家建构与地方、民族整合的滞后,传统与非传统安全密切交织,以及外部力量... 详细信息

分裂主义作为现代民族国家体系的伴生物,是一种相对普遍而又特殊的国际现象。伴随着世界三次民族主义浪潮,分裂主义在全球的肆虐未有穷期。特别是在后冷战时代,国家建构与地方、民族整合的滞后,传统与非传统安全密切交织,以及外部力量深度介入他国民族、统一问题等系列因素,进一步刺激了分裂主义在部分国家的发展并对地区乃至国际安全构成了消极的冲击。如何认识分裂主义的由来与发展?在国际政治视域内,分裂主义研究存在哪些焦点与分歧?我国分裂主义的相关研究如何更好地回应反分裂斗争实践的迫切需求,有哪些突破方向?为此,本刊特约记者兰州大学中亚研究所助理研究员靳晓哲专访兰州大学中亚研究所李捷教授。李教授的主要研究领域包括分裂主义理论、反分裂与国家安全等,著有《国外维护国家统一的路径与实践研究》《国家统一中的认同建设》《分裂主义及其国际化研究》《推进新疆社会稳定与长治久安战略》等。

关键词：分裂主义后冷战时代中亚研究所深度介入国家建构民族整合李捷外部力量

The Role of Seal and Source Rocks in Fluid-rock Interactions and their Reservoir Effects within the Carbonate Deep Burial Realm

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Acta Geologica Sinica(English Edition) 2022年第4期96卷 1353-1361页

作者： LI jie CAI Zhongxian Hubei Key Laboratory of Oil and Gas Exploration and Development in Hubei Province Wuhan 430074China Key laboratory of Tectonics and Petroleum Resources China University of GeosciencesWuhan 430074China

Discoveries of deep high-quality carbonate reservoirs challenged the general understanding on the evolution of porosity decreasing with depth.New mechanisms of pore generation and preservation in the deep realm require to be proposed.Dolostones in the Feixianguan and Dengying Formations experienced maximum depths in excess of 8000 m,but still retained high porosity.Petrographic observation and homogenization temperatures help to identify products of deep fluid-rock interactions,visual and experimental porosity were used to quantify reservoir effects,the distribution of products finally being plotted to unravel the mechanisms.Th data reveal that thermochemical sulfate reduction(TSR),burial dissolution and quartz cementation are typical deep fluid-rock interactions.The SO_(4)^(2-)of residual porewater sourced from the evaporative dolomitizing fluid was supplied for TSR in the hydrocarbon column,the TSR-inducing calcite cements were homogeneously dispersed in the hydrocarbon column.Quartz cementation was caused by the increasing acidity and Si-rich residual porewater in the oil column.Burial dissolution is forced by organic acid and limited in oil-water contact.This study suggests that seal and source rocks not only play important roles in hydrocarbon accumulation,but also have a general control on the deep fluid-rock interactions and porosity evolution in the deep burial realm.

关键词： TSR quartz cement burial dissolution mesogenetic pores oil water contact

Stochastic fatigue damage model for concrete under complex stress states

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Science China(Technological Sciences) 2022年第11期65卷 2641-2648页

作者： WANG YanPeng LI jie School of Civil and Transportation Engineering Guangdong University of TechnologyGuangzhou 510006China School of Civil Enginering Tongji UniversityShanghai 200092China

This paper presents a stochastic fatigue damage model for concrete subjected to complex stress states.A constitutive framework considering the tensile and shear damage mechanisms and elastic and plastic energy dissipations is employed.The damage law is established through a multiscale analysis of the damage evolution mechanism.Validation results against test data show that the model can effectively predict the static strength,stress-strain curve,fatigue life,and scattering range of concrete under various multidimensional loading scenarios.

关键词： concrete fatigue stochastic damageevolution complex stress states multiscale

Honokiol Prevents Intestinal Barrier Dysfunction in Mice with Severe Acute Pancreatitis and Inhibits JAK/STAT1 Pathway and Acetylation of HMGB1

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CHINESE JOURNAL OF INTEGRATIVE MEDICINE 2023年第6期30卷 534-542页

作者： li, jie Chen, Ya-feng Gao, Lei li, Yi-jie Feng, Dian-xu Shanghai Univ Tradit Chinese Med Dept Gen Surg Putuo Hosp Shanghai 200062 Peoples R China

Objective: To investigate the effect of honokiol (HON) and the role of high-mobility group protein B1 (HMGB1) on the pathogenesis of severe acute pancreatitis (SAP). Methods: Thirty mice were numbered according to weight, and randomly divided into 5 groups using a random number table, including control, SAP, SAP and normal saline (SAP+NS), SAP and ethyl pyruvate (SAP+EP), or SAP+HON groups, 6 mice in each group. Samples of pancreas, intestine, and blood were collected 12 h after SAP model induction for examination of pathologic changes, immune function alterations by enzyme linked immunosorbent assay (EliSA), and Western blot. In vitro experiments, macrophages were divided into 5 groups, the control, lipopolysaccharide (LPS), LPS+DMSO (DMSO), LPS+anti-HMGB1 monoclonal antibody (mAb), and LPS+ HON groups. The tight connection level was determined by transmission electron microscopy and fluorescein isothiocyanate-labeled. The location and acetylation of HMGB1 were measured by Western blot. Finally, pyridone 6 and silencing signal transducer and activator of the transcription 1 (siSTAT1) combined with honokiol were added to determine whether the Janus kinase (JAK)/ STAT1 participated in the regulation of honokiol on HMGB1. The protein expression levels of HMGB1, JAK, and STAT1 were detected using Western blot. Results: Mice with SAP had inflammatory injury in the pancreas, bleeding of intestinal tissues, and cells with disrupted histology. Mice in the SAP+HON group had significantly fewer pathological changes. Mice with SAP also had significant increases in the serum levels of amylase, lipase, HMGB1, tumor necrosis factor- alpha, interleukin-6, diamine oxidase, endotoxin-1, and procalcitonin. Mice in the SAP+HON group did not show these abnormalities (Plity, decreased the levels of junctional adhesion molecule C, and elevated intercellular permeability (P<0.01). HON treatment blocked th

关键词： severe acute pancreatitis intestinal barrier dysfunction honokiol high-mobility group protein B1 Janus kinase signal transducer and activator of transcription 1 JAK-STAT PATHWAY INFLAMMATION MANAGEMENT

Neural Stem Cell Competition

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Neuroscience Bulletin 2024年第2期40卷 277-279页

作者： Yanan li jie He State Key Laboratory of Neuroscience Institute of NeuroscienceCenter for Excellence in Brain Science and Intelligence TechnologyChinese Academy of SciencesShanghai 200031China University of Chinese Academy of Sciences Beijing 100049China

Cell competition is an adaptive surveillance mechanism to ensure the robustness of developmental outputs,maintain tissue integrity,and regulate tumor progression in multicellular organisms,which is highly conserved from invertebrates to vertebrates[1].At the cellular level,cell competition represents a non-cell-autonomous process in that cells can sense the fitness of their neighbors through cellular interactions,thereby eliminating low-fitness cells and expanding high-fitness counterparts,however,cells develop normally in homogenous populations.

关键词： thereby maintain eliminating

Effect of Dangfei liganning capsule(当飞利肝宁胶囊) on liver X receptor α/steroid regulatory element binding protein-1/fatty acid synthase signal pathway in rats with metabolic-associated fatty liver disease

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Journal of Traditional Chinese Medicine 2022年第6期42卷 940-947页

作者： li Xiaoling SUN Fengxia SHANG Zimeng ZHANG Yingxue LI jie ZHANG Qiuxiang Infections Department Beijing Hospital of Traditional Chinese MedicineCapital Medical UniversityBeijing 100010China Infections Department Beijing Hospital of Traditional Chinese Medicine Shunyi BranchBeijing 101300China

OBJECTIVE: To study the mechanism of Dangfei liganning capsule(当飞利肝宁胶囊) in the treatment of rats with metabolic associated fatty liver disease(MAFLD). METHODS: Totally 48 specific pathogen free SpragueDawley male rats were randomly divided into normal Group, model group, Dangfei liganning high, moderate, and low-dose groups and Essentiale group which were fed with high fat diet for 8 weeks, and gavage and molding were carried out simultaneously. Dangfei liganning high, middle and low-dose group were given 0.27, 0.135 and 0.0675 g·kg-1·d-1 respectively by gavage, Essentiale group was given 0.123 g·kg-1·d-1 by gavage, the same amount of distilled water was given by gavage in the normal group and the model group. The rats were weighed at the 0th week, 2nd week, 4th week, 6th week and 8th weekend respectively. The rats were sacrificed at the end of the 8th week. Serum levels of alanine aminotransferase(ALT), alanine aminotransferase(AST),triglyceride(TG), total cholesterol(CHO), high-density lipoprotein cholesterol(HDL-C), low-density lipoprotein (LDL-C), total protein(TP), albumin(Alb), globulin(GLB), total bilirubin(TBIL), direct bilirubin(DBIL), tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) were measured. The levels of liver tumor necrosis factor-α(TNF-α), interleukin-6(IL-6) and liver pathology [hematoxylin and eosin(HE) staining, oil red O staining] were detected. The expression levels of liver X receptor α(LXRα), steroid regulatory element binding protein-1(SREBP-1) and fatty acid synthase(FAS) were detected by immunohistochemistry, Western blot and reverse transcription-polymerase chain reaction reverse transcription-polymerase chain reaction. RESULTS: From the beginning to the 8th week, the growth rate of body weight in the Dangfei liganning highdose group was slower than all other groups. There was no significant difference in ALB level in all groups(P > 0.05). Compared with the model group, the levels of ALT, AST, LDL-C, TG, CHO, TP, GLB, TBIL, DBIL, IL-6, TNF-α were significantly decreased and HDL

关键词： metabolic associated fatty liver disease liver X receptors steroid regulatory element binding protein-1 fatty acid synthases signal transduction Dangfei liganning capsule